1. Field
This disclosure relates to a one-way clutch that is used as a brake mechanism for fixing either one of two rotational members that rotate relative to each other and thereby allowing rotation of the either one of the two rotational members in one rotational direction while restricting rotation thereof in the other rotational direction.
2. Description of Related Art
A one-way clutch can function as a brake mechanism for unrotatably fixing either one of two rotational members of the one-way clutch that rotate relative to each other and thereby restricting rotation of the either one of the two rotational members in only one direction. For example, a rotational direction of a rotational body, such as an output shaft of an engine or a motor, can be restricted in only one direction by fastening the one rotational member of the one-way clutch to the rotational body and fixing the other rotational member to a fixing body, such as an engine block or a transmission housing. The one rotational member of the one-way clutch and the rotational body are typically fastened by a bolt.
The disclosure related to a structure of the one-way clutch as described above and an assembling method thereof is described in Japanese Patent No. 5288051. The one-way clutch described in this Japanese Patent No. 5288051 is assembled to the engine block by using a jig that has a male screw section and a pin-shaped section for positioning. More specifically, first, an inner race, an outer race, and an engagement member that constitute the one-way clutch are integrally and temporarily assembled by the male screw section of the jig. A flywheel is positioned with respect to the temporarily assembled one-way clutch by the pin-shaped section of the jig. Then, these one-way clutch and flywheel are fixed to a flange that is provided at a tip of a crankshaft by the bolt.
As in the configuration described in above Japanese Patent No. 5288051, it is common that the one-way clutch is fixed to the flange of the rotational body that is formed with a screw hole by the bolt, for example. Torque can reliably be transmitted between the one-way clutch and the rotational body when the one-way clutch is fixed by the bolt. However, when the bolt is used to fasten the one-way clutch and the rotational body, a phase of a bolt hole, which is formed in the one-way clutch, and a phase of the screw hole, which is formed in the flange of the rotational body, have to be coincided with each other during assembly. When the bolt is fastened in a state where the phase of the bolt hole and the phase of the screw hole are not coincided with each other, the screw hole and a screw head of the bolt possibly interfere with each other, and thus an appropriate bolt fastening force cannot possibly be obtained.
In particular, in the case where the one-way clutch is used as the brake mechanism as described above, relative rotation between the two rotational members of the one-way clutch is limited to the one direction. Thus, there is a case where the phase of the bolt hole and the phase of the screw hole are not easily coincided with each other. It should be noted that the phase of the bolt hole and the phase of the screw hole can easily be coincided with each other by increasing a radius of the bolt hole. However, an area of a seat surface that receives an axial force from the bolt during fastening is reduced by an increase in the radius of the bolt hole. Thus, also in this case, the appropriate bolt fastening force cannot possibly be obtained.